how much do you want to slow it down, and is it interlaced?
i don’t have twixtor, but if it is anything like timewarp, you should be able to enter the speed you want it to play at (say 50%) and choose the interpolation method to generate the in between frames (like pixel motion, frame mix…).
you can do a pretty good job of slowing interlaced footage down 50%, by choosing separate fields (with correct dominance) from the interpret footage setting and setting the frame rate to half the actual frame rate, then putting that in a comp with a standard frame rate.
if its not interlaced, or you used the deinterlace method described above but want to slow it down further, you can just set the frame rate to a lower rate (using half, or quarter, if it was interlaced, of the actual frame rate can look pretty good in many cases). put that in a standard frame rate comp, set the frame blending to pixel motion and enable frame blending in preview.
Kevin Camp
Designer – KCPQ, KMYQ & KRCW